1. Field of the Invention
The present invention relates to a method and apparatus for measuring the extent of damage to an organic layer included in a thin film encapsulation of an organic light-emitting display device.
2. Description of the Related Art
An organic light-emitting display device typically includes a display unit in which an emissive layer formed of an organic material is interposed between an anode electrode and a cathode electrode. When a voltage is applied between the anode electrode and the cathode electrode, holes implanted into the anode electrode and electrons implanted into the cathode electrode recombine in the emissive layer to generate excitons, and light is emitted as the excitons transfer from an excited state to a ground state, thereby forming an image.
Importantly, if the emissive layer of the display unit directly contacts water, the light-emitting characteristics thereof deteriorate, and, thus, the display unit may be covered with an encapsulation member in order to prevent this. A stacked thin film encapsulation formed by alternately stacking at least one organic layer and at least one inorganic layer has been frequently used as an encapsulation member. Among the stacked layers constituting the thin film encapsulation, the function of preventing penetration of moisture into the display unit is performed mainly by the inorganic layer(s), and the function of giving flexibility to the thin film encapsulation is performed by the organic layer(s).
However, when an organic layer and an inorganic layer are stacked adjacent to each other, the organic layer may frequently be damaged. That is, while an inorganic layer is typically formed by using a plasma process, an underlying organic layer, which is formed in advance, may also be affected by the plasma and deteriorate, and thus defects in the organic layer, such as progressive dark points, may occur frequently. This may cause significant adverse effects in the product reliability of an organic light-emitting display device (OLED). However, there has heretofore been no method to check the degree of damage caused by exposure of an organic layer in a thin film encapsulation to plasma. Such a method would enable an OLED fabricator to handle this problem.
Accordingly, a method of determining the degree of damage to an organic layer in a thin film encapsulation due to plasma exposure is necessary in order to provide an OLED fabricator with means for determining ways of mitigating this damage.